Disc drives are the primary devices employed for mass storage of computer programs and data. The advantages of disc drive technology over other means of data storage include a lower cost per unit of storage capacity and a generally higher transfer rate. Within a disc drive, a suspension supports a hydrodynamic air bearing slider close to a rotating disc. The suspension supplies a downward force that counteracts the hydrodynamic lifting force developed by the slider's air bearing. The slider carries a transducer head for communication with individual bit positions on the rotating disc.
The suspension includes a load beam and a gimbal, which is attached to the load beam. The gimbal is positioned between the load beam and the slider. Typically, the gimbal is welded to the load beam and is connected to the slider by an adhesive. The gimbal resiliently supports the slider and allows it to pitch and roll while it follows the topography of the rotating disc. The slider, the suspension, and an interconnect (flexible circuit, for example, that carries electrical signals between the transducer head and drive electronics) form a head gimbal assembly (HGA).
A disc drive must operate in a wide range of ambient temperatures, where the particular temperature range depends on the product segment (for example, disc drives for the automotive market must operate in a larger temperature range than disc drives for the server market). A change in ambient temperature causes an air bearing surface (ABS) of the slider to deform due to differing thermal expansion coefficients of materials comprising the slider, the suspension, and the interconnect. The deformation of the ABS causes undesirable shifts in fly height, pitch, and roll.
Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.